On-vehicle disk brake lathes classically employ a worm drive to provide power from a motor to a lathe spindle. The motor is aligned with and coupled to a worm shaft on which a worm is mounted, the worm rotating about a worm shaft axis. The worm in turn engages a worm gear on a spindle shaft of the lathe spindle, providing the worm drive. The spindle shaft rotates about a spindle axis that is perpendicular to the worm shaft axis, and thus is also perpendicular to a motor axis of rotation when the motor is coupled to the worm shaft.
The lathe has a cast housing, which is assembled around the worm and the worm gear, as well as around a portion of the worm shaft and a portion of the spindle shaft, forming a lathe housing. Seals and bearings are provided for the worm shaft and the spindle shaft to form a sealed unit to house the worm drive.